MP4 Metadata Tag/Key List (work in progress)

MP4 Metadata Tag/Key List (work in progress)

Hello folks,

Following up on my previous email regarding ffmpeg mp4 metadata writing I
have compiled the attached list of what I was able to find. This is the
informational metadata for things like title, artist, episode, cover art,
etc.

If the attached file can't be opened let me know. I have marked this as V1.

I have to say I'm quite surprised that metadata is not better documented
given it's one of the great additions to media files in recent years
(IMHO). :-) For example a lot of the itunes references I found weren't even
on the Apple site. They were on other sites not even affiliated with Apple.
Added to this some pages only provided half the information and I found a
bunch of references that seemed to contradict each other. It's clear as
mud. :-)

Things to note:
1. I'm not sure if this is a complete list. If not then feel free to add to
it or let me know and I will update.
2. Does this make sense to go into the wiki (even if it's just the ffmpeg
portion.
3. Can the current set of ffmpeg tags be extended to include the tags with
no ffmpeg equivalent or is there some reason these can't be added? For
example "TV Episode (tves) would be good to have to round out the current
set of TV tags along with a lot of the other mp3 tags given ffmpeg can be
used for mp3 as well.
4. The quicktime column is a work in progress. Most of these are the same
as itunes but I found a few differences which I'm documenting. From most of
my research it seems like the itunes tags are the ones used as a reference
point (but correct me if I'm wrong).
5. There are a few highlighted in yellow. These are additional ffmpeg tags
I found beyond a list that Gyan had posted. I'm not sure if these are valid
or whether they're from an older version of ffmpeg and are no longer in use.